Free birthday tool
What's my zodiac sign?
Choose a birthday to see its Western zodiac sign. If it falls near a sign change, add the year, and the calculator works out the exact minute the Sun moved.
Find a zodiac sign
- Aries , March 21 to April 19
- Taurus , April 20 to May 20
- Gemini , May 21 to June 20
- Cancer , June 21 to July 22
- Leo , July 23 to August 22
- Virgo , August 23 to September 22
- Libra , September 23 to October 22
- Scorpio , October 23 to November 21
- Sagittarius , November 22 to December 21
- Capricorn , December 22 to January 19
- Aquarius , January 20 to February 18
- Pisces , February 19 to March 20
How zodiac dates work
Four turning points
Aries starts at the March equinox, Cancer at the June solstice, Libra at the September equinox and Capricorn at the December solstice. These four dates anchor the whole year.
Three signs a season
Between each pair of turning points sit three signs of about a month each: one that begins the season, one that holds the middle and one that leads into the next.
Why the dates move
The Sun takes about 365.24 days to come round, a little longer than a calendar year. Each sign starts about six hours later every year until a leap day pulls it back, so the first day of a sign moves by a day.
Dates, traits and gift ideas for every sign
How the calculator works
Where the Sun is
The Sun's position comes from the VSOP87 theory of the planets, in the shortened form Jean Meeus gives in Astronomical Algorithms, with corrections for nutation and aberration.
Checked against the Naval Observatory
We compare the results with every equinox and solstice the US Naval Observatory lists from 2016 to 2036, 84 moments in all. None is more than two minutes off.
Astronomers' time and clock time
Astronomers count in Terrestrial Time, which runs about a minute ahead of clock time. The calculator converts using the NASA formulas by Espenak and Meeus, then shows the moment in the time zone you choose.
What it does not do
Exact times cover 1900 to 2100. Without a birth year, the calculator uses the common dates. The traits and gift ideas on these pages come from astrological tradition, not from astronomy.
Sources
- Jean Meeus, Astronomical Algorithms, 2nd edition. Willmann-Bell, 1998.
- Earth's Seasons: Equinoxes, Solstices, Perihelion and Aphelion. US Naval Observatory.
- Fred Espenak and Jean Meeus, Polynomial Expressions for Delta T. NASA Goddard Space Flight Center.
- Astrology in the Hellenistic period. Encyclopaedia Britannica.
- 88 Officially Recognized Constellations. NASA StarChild.
Last checked October 2026.
Frequently asked questions
What is my zodiac sign?
Your zodiac sign, or Sun sign, is the sign the Sun was in when you were born. Enter your birthday above to see it. For most dates the month and day are enough. If you were born within a day of a sign change, add your birth year, and the calculator works out the exact moment the Sun changed sign that year.
Is a star sign the same as a zodiac sign?
Yes. Star sign, Sun sign and zodiac sign all mean the same thing: the sign the Sun was in on the day you were born. Star sign is more common in the UK, Ireland, Australia and India, and zodiac sign in the US.
Does my birth year change my zodiac sign?
Only if you were born near a sign change. The Sun enters each sign at a slightly different time each year, up to about a day apart, because the calendar year and the solar year are not the same length. On those days the year, and sometimes the hour, decide the sign. Everywhere else, the year makes no difference.
Why do different websites show different dates for the same sign?
Most tables round each sign to whole days, and they round in different directions. Scorpio is often listed as starting on October 23 and sometimes on October 24. Both are right in some years. This page uses the most common dates and gives an exact answer when you add a birth year.
What does it mean to be born on the cusp?
Being born on the cusp means your birthday falls on a day when the Sun changed sign. In astrology you still have one Sun sign, the one the Sun was in at the moment of your birth. Add your birth year and, if asked, your birth time to see which side of the change you were born on.
Are zodiac dates different in the Southern Hemisphere?
No. The dates are the same everywhere because they follow the Sun's path, not the weather. The seasons are reversed, though. Aries starts at the March equinox, which is the beginning of spring in the north and of autumn in the south.
Is there a 13th zodiac sign, Ophiuchus?
The constellation Ophiuchus does sit on the Sun's path, roughly from late November to mid December. Western astrology does not use constellations to set the dates, though. It divides the Sun's yearly path into twelve equal parts starting at the March equinox, so there are twelve signs and Ophiuchus is not one of them.
How is this different from my Vedic or sidereal sign?
Vedic (sidereal) astrology measures the signs against the fixed stars. Western (tropical) astrology measures them from the March equinox. The two have drifted about 24 degrees apart over the centuries, so for most people the sidereal sign is the one before their Western sign. This calculator gives the Western sign.
What about my Moon sign and rising sign?
Those need your exact birth time and place, because the Moon changes sign every two to three days and the rising sign changes about every two hours. This calculator finds the Sun sign, which is what people usually mean by their zodiac sign.
